Not applicable.
This invention relates to vascular growth, and more particularly to apparatus and methods for using extremely cold temperatures to promote angiogenesis.
Angiogenesis relates to the formation of blood vessels in living tissue. Not surprisingly, vascular growth or the lack thereof significantly affects living tissue. In adults, the body""s network of blood vessels is stable. However, under certain circumstances, such as physical injury, the body causes new blood vessels to grow. Various drug and gene therapies are under study that show promise in amplifying angiogenesis where it naturally occurs, and promoting it where it does not otherwise occur. Drug and gene therapy, however, can not only be difficult to localize, but the mechanisms by which they operate are also poorly understood and may cause unwanted side effects. It would therefore be desirable to provide an alternative method of promoting vascular growth.
The present invention provides a method of promoting blood vessel growth using extremely cold temperature. The cold temperature is used to create one or more cold affected zones in tissue, wherein the treatment is of a character that injures or traumatizes the tissue enough to provoke an angiogenic response, but yet does not completely kill all of the cells in the cold affected zone. In other words, the present invention seeks to obtain a balance between minimizing trauma to tissue while maximizing angiogenic response.
In an exemplary method, a cryocatheter having a thermally transmissive regon is provided. The cryocatheter is placed proximate an area of tissue to be treated and cooled to a temperature sufficient to traumatize the area of tissue. The tissue can be rewarmed and cooled again one or more times. Prior, during or after tissue cooling the tissue can be mechanically traumatized by the creation of single or multiple pricks, scores, tears or channels.